There has been cardiotoxicity associated with fluorinated pyrimidine therapy, including myocardial infarction, angina, dysrhythmias, cardiogenic shock, sudden death, ECG changes, and cardiomyopathy (higher risk if coronary artery disease). May cause severe diarrhea. May cause hand-and-foot syndrome (palmar-plantar erythrodysesthesia or chemotherapy-induced acral erythema). May cause necrotizing enterocolitis (typhlitis). Use with caution in bone marrow suppression. Rare and unexpected severe toxicity (diarrhea, neutropenia, neurotoxicity, stomatitis) may be attributed to DPD deficiency. Use with caution in hepatic or renal impairment. Use with caution in patients who have received alkylating therapy. Capecitabine may increase the anticoagulant effects of warfarin. Use with caution in patients ≥80 years of age. Use with caution in patients who have received extensive pelvic radiation. Sedation is common and may also cause dizziness or insomnia. Neutropenia is common (use caution with clozapine and carbamazepine). Risk of reversible stomatitis, abnormal taste, and taste disturbance. Capecitabine is clastogenic to human peripheral blood lymphocytes in vitro but is not clastogenic to mouse bone marrow (micronucleus test) in vivo.